Dickcissel (Spiza americana)

The dickcissel is classified as Least Concern (LC) on the IUCN Red List (1).

The sparrow-like dickcissel (Spiza americana) is one of North America’s most abundant breeding birds (2) (3). It is a relatively small songbird, with a stout, pointed bill, light-grey belly and a brown back which is streaked with black (2) (3).

The male dickcissel is larger than the female and has a streaked, greyish head and a black, V-shaped throat patch which contrasts with the bright yellow of its breast feathers (2) (3). Both sexes have a yellow stripe over the eye and blackish wing and tail feathers (3). Immature dickcissels are generally similar in appearance to the adult female, but have much duller plumage (2).

The song of the dickcissel can commonly be heard during the summer months in its prairie grassland breeding grounds (2). It has a simple, dry song that usually consists of two introductory notes followed by a brief pause, then five or six main notes (2) (3). The simple song is then repeated rapidly, in succession (2).

During the breeding season, the dickcissel can be found in central North America, ranging as far north as Minnesota and North Dakota, and south to Texas and South Louisiana. From east to west it ranges from the states of Ohio, Kentucky and Tennessee, west as far as Colorado (2).

The dickcissel migrates south in large numbers to overwinter, with its winter range extending from western Mexico to northern parts of South America (4).

The preferred habitat of the dickcissel is open grassland such as prairies or lightly grazed pasture lands (3). It is also found in overgrown, weedy fields and roadside vegetation and utilises wetlands and marshes during its migration (2) (3) (4).

The dickcissel is omnivorous and, during the summer breeding months, feeds on a range of seeds and invertebrates (2) (3). Seeds are either foraged for on the ground or plucked directly from the plant whilst perched on a plant stem. The outer covering of the seed is then removed before being eaten (2). On migration and during the winter, the dickcissel is highly gregarious and forms flocks, some of which are so large they may contain between 10 and 30 percent of the global population. During this time the dickcissel is described as being ‘granivorous’ as its diet consists mainly of seeds, often from food crops (2).

The breeding season for the dickcissel varies depending on location, but usually begins in May or June. The male dickcissel will defend a territory that contains both suitable nesting and foraging areas, and will vigorously chase away any intruding males (2). Males with territories containing the best nest sites will attract more females (2).

The female alone is responsible for selecting the nest site, building the nest and then brooding and raising the young. The dickcissel’s nest is usually placed slightly above the ground, in dense vegetation, and consists of a bulky cup woven out of weed and grass stems (2) (3). A clutch of 3 to 6 pale blue eggs is laid and is incubated for around 12 to 13 days. The young dickcissels are fed on a variety of invertebrates and leave the nest at around eight to ten days old (2).

Although numerous and widespread, the dickcissel faces a number of threats throughout its range (2) (4). It is particularly persecuted in its wintering grounds in Venezuela, where large flocks are illegally poisoned in order to protect food crops (2) (4). One farmer is reported to have killed over a million birds in this manner (2). The dickcissel is also hunted and eaten by people using guns, slingshots or even cars driven through roosting flocks (2).

The dickcissel is also potentially vulnerable to alterations to its summer breeding habitat, with native grasslands being converted into rows of crops and thus reducing the nesting habitat available (2).

Currently, the only specific conservation measure aimed at the dickcissel is the proposed control of the illegal killing of large flocks in Venezuela (2). By encouraging farmers to protect their crops with non-lethal methods, it is hoped that the future of the dickcissel will remain secure (2).